This invention relates to color printing, and more particularly, to color laser printing systems. Such structures of this type, generally, employ a rotatable, carousel type shuttle color printer with an all in one electrophotographic (EP) cartridge having a high capacity toner reservoir.
It is known, in shuttle type color printers to employ a paper drive. Exemplary of such of prior art is commonly assigned U.S. Pat. No. 5,978,642 (""642) to D. J. Arcaro et. al., entitled xe2x80x9cColor Printer with Shuttle Type Paper Drive and Method.xe2x80x9d While the ""642 reference utilizes a toner cartridge which includes four separate colors (magenta, yellow, cyan, and black) located along the outside of a single photoconductor drum, these four separate colors each have a separate toner reservoir. Presently, these toner reservoirs contain approximately the same amount of toner. However, it is well known that the black toner is used more frequently for printing, especially for printing text, and this black toner reservoir requires replacement more frequently than the other three colors. Therefore, while the printer of the (""642) reference is capable of color printing, it is desirable to include a black toner reservoir which can hold more black toner.
It is also known, in color image forming apparatus, to employ rotatable image forming units. Exemplary of such prior art is U.S. Pat. No. 5,809,380 (""380) to N. Katakabe et. al., entitled xe2x80x9cColor Image Forming Apparatus with Plural Color Units.xe2x80x9d While the ""380 reference utilizes rotatable image forming units and a laser beam which is traversed through the image forming units, the apparatus also does not employ a high capacity black toner cartridge. Also, the ""380 reference employs expensive optics located within the rotatable image forming unit. Consequently, a more advantageous color printer would be presented if a high capacity black toner cartridge could be employed, while avoiding the use of expensive optics located within the rotatable image forming unit.
It is apparent from the above that there exists in need in the art for a carousel type shuttle color printer with all in one EP cartridges, which at least equals the printing characteristics of the known color printers, but which at the same time contains a high capacity black toner cartridge and avoids the use of optics in the cartridge. It is a purpose of this invention to fulfill this and other needs in the art in a manner more apparent to the skilled artisan once given the following disclosure.
Generally speaking, this invention fulfills these needs by providing a carousel type shuttle color printer, comprising an exposure device including a laser beam periodically emitted from the exposure device and a rotatable color image forming unit having a plurality of different color development stations, wherein one of the plurality of development stations includes a high capacity toner reservoir such that the laser beam from the exposure device can be traversed substantially through the high capacity toner reservoir.
In certain preferred embodiments, the high capacity toner reservoir contains approximately twice as much black toner as a conventional black toner reservoir. Also, the carousel type shuttle color printer can print in a simplex or duplex mode. Finally, the printer avoids the use of optics located within the rotatable color image forming unit.
In another further preferred embodiment, the high capacity toner cartridge allows the carousel type shuttle color printer to continue printing longer without having to frequently replace the most frequently used toner color, which is usually the black toner.
The preferred color printer, according to this invention, offers the following advantages: excellent printing characteristics; ease of assembly and repair; good stability; excellent durability; decreased downtime; and good economy. In fact, in many of the preferred embodiments, these factors of printing characteristics, durability, decreased downtime, and economy are optimized to an extent that is considerably higher than heretofore achieved in prior, known color printers.
The above and other features of the present invention, which become more apparent as the description proceeds, are best understood by considering the following detailed description in conjunction with the accompanying drawings wherein like characters represent like parts throughout the views: